As opposed to all the other big cats, lions have developed a group way of life. These prides generally consist of one to seven males and one to eighteen females. The male lion, large and powerful, plays a role of protecting the group, while lionesses, being smaller and more discreet, are redoubtable predators.
Young males will stay in the pride in which they were born for almost two years and start hunting once sexual maturity has been achieved. They then form coalitions of young males and try to usurp any adult already in place. If they attain their aim, they kill the young of the previous male, thus making the females go on heat again, that is making them ready to reproduce once again. In contrast to the males, females remain in the pride all their lives, which helps to avoids in-breeding.
During the passage of power from one male to the other, each of the two parties must demonstrate all their strength and aggression. This show of force is a reflection of the quality of their genes. Thus it is generally the females, looking on, who decide whether to accept a new parent for their offspring.